Swiped from the vorbis docs
    * one channel - the stream is monophonic
    * two channels - the stream is stereo. channel order: left, right
    * three channels - the stream is a 1d-surround encoding. channel order: left, center, right
    * four channels - the stream is quadraphonic surround. channel order: front left, front right, rear left, rear right
    * five channels - the stream is five-channel surround. channel order: front left, center, front right, rear left, rear right
    * six channels - the stream is 5.1 surround. channel order: front left, center, front right, rear left, rear right, LFE
    * seven channels - the stream is 6.1 surround. channel order: front left, center, front right, side left, side right, rear center, LFE
    * eight channels - the stream is 7.1 surround. channel order: front left, center, front right, side left, side right, rear left, rear right, LFE
    * greater than eight channels - channel use and order is undefined